The present invention relates to an optical waveguide type device having an optical semiconductor and an optical waveguide and, more particularly, to a structure for coupling the semiconductor and waveguide, and a coupling method of the same.
Optical waveguide type devices, like electronic devices, can be produced on a quantity basis and can be provided with advanced functions and a highly integrated configuration. To further enhance the functions and integration, there is available a coupling structure having an optical semiconductor in a waveguide type device and connects the semiconductor directly to an optical waveguide.
It has been customary with the structure optically coupling the optical semiconductor to the optical waveguide to cause the semiconductor to emit light by flowing a current therethrough, and monitor light coming out of the waveguide so as to adjust the position of the semiconductor. A coupling structure capable of coupling an optical semiconductor to an optical waveguide without any positional adjustment is disclosed in, for example. Japanese Patent Laid-Open Publication No. 61-87113. In this kind of coupling structure, a guide is formed on an optical waveguide substrate beforehand, and an optical member and optical semiconductor are fitted in the guide.
To couple an optical semiconductor to an optical waveguide via a lens with efficiency, it is necessary that the semiconductor and lens be each positioned with accuracy less than about 1 .mu.m relative to the waveguide. The conventional coupling structure mentioned above positions the semiconductor and lens by the guide without adjustment, so that the guide has to be provided with an extremely accurate configuration. However, this is extremely difficult since the guide suffers from errors when formed by patterning or etching. Another problem is that a step of forming the guide is needed in addition to a step of forming the waveguide, complicating the entire process and, therefore, limiting productivity. In addition, since the guide is located in the vicinity of the end of the waveguide, it is impossible to measure, before mounting the semiconductor, the loss and other characteristics of the waveguide by abutting an optical fiber against the end of the waveguide.